Electrical conductor



July 9, 1940. w. T. BARRANS El AL 8. R G/RARD JAN- Z ATTOR EV WWEAR/FANS INVENTORS. R M COLE Patented July 9, 1940 UNITED STATES PATENTOFFICE ELECTRICAL CONDUCTOR York Application March 3,

8 Claims.

This invention relates to an electrical conductor and more particularlyto an extensible retractile cord.

An object of the invention is to provide a con- 6 ductor cord which maybe readily bent or coiled.

In accordance with one embodiment of the invention a retractile cord ofhelical form is provided having a braided covering in which the outerportions of the helical convolutions are 10 braided progressively onestrand over one strand and under the next strand, while the innerportions are braided progressively one strand over two strands and undertwo strands.

A full understanding of the invention may be 15 had by reference to thefollowing description taken in conjunction with the accompanyingdrawing, in which:

Figure 1 is a detailed view of a helically coiled conductor embodyingthe invention; 20 Figure 2 is a plan development showing the inner andouter portions of one type of braid, and

Figure 3 is a plan development of another type of braid.

In making a braid covered electrical cord of the extensible retractiltype it is common practice to provide elastic material underlying thebraid to cause the cord, which usually consists of several conductors,to assume a helically coiled form. The braid may be applied to theconductor in a braiding machine of the type disclosed in the patent toMiller, 1,602,442, of October 12, 1926. The braid is applied to astraight portion of the cord with the elastic material 4 under tensionand when the cord is released from the machine the elastic materialtends to draw it into helical form. As the conductor is bent in a helixthe inner portion'of a convolution of the braided material has atendency to be compressed and the outer portion of a convolution of thebraid has a tendency to be stretched. When a braided covering is made insuch a manner that one yarn passes progressively over one yarn and underthe next, a plain braid is made which resists compression to a highdegree.

When, however, the braid is formed in such a manner that a yarn passesprogressively over two yarns and under two yarns, there is lessresistance to compression of the braided covering.

1939, Serial No. 259,509

inner portions of the convolutions are braided progressively one yarnover two yarns and under the next two which permits the cord to coilwith considerably greater facility. Referring, for instance, to Figure2, the right hand half of the figure represents a one over one braidwhich forms the outer half ofthe braid ,and the left hand half of thefigure represents a one over two 'braid which forms the inner half ofthe braid. In order to obtain this type of braid on a standard Wardwelltype of braider, it is simply necessary to properly arrange thedeflectors as described in the above referred. to patent to Miller. In asimilar manner cords may be made in which the outer portion of the braidis made one over one, the intermediate portion of the braid along theneutral bending axis may be made one over two and the inner portions ofthe braid one over three. In some cases it has been found to bedesirable to braid the outer portion of the braid one over two and theinner portion of the braid one over three, or even of a higher order ordegree. In fact, a very satisfactory cord may be made by notinterbraiding the inner yarns of the convolutions at all, simply servingthem onto the conductor while the outer portion of the yarn isinterbraided. The resistance to bending of the conductor is decreased inall cases by making the overlapping of the yarns on the inner sideof-the convolutions of a higher order or degree than the overlapping onthe outer portion of the convolutions.

Fig. 3 shows in plan development a braided cover for a cord in which thebraid between lines a and b is braided one yarn over two yarns, thebraid between lines D and c is braided one yarn over one yarn, the braidbetween lines and d is braided one yarn over two yarns, and the yarnbetween lines d and a is unbraided. When this covering is on a helicallycoiled cord the braid between lines D and c is on the outside of aconvolution, and on each side thereof on the neutral bending axis of thecord the yarn is braided one yarn over two. On the inside of aconvolution the yarn is unbraided.

It will be understood that the invention herein described andillustrated is merely illustrative of the invention and that manychanges and modifications may be made therein without departing from thespirit and scope of the invention.

What is claimed is: 1. An electrical cord comprising a conductor.

having a covering of strand material having circumferentially differentorders of interbraiding of the strand material to provide greatercompressibility on one side than on the-other to facilitate bending ofthe cord.

2. Anelectrical cord comprising .a conductor having a covering ofbraided strand material in which one side of the covering isinterbraided' to a higher degree than the other to facilitate bending ofthe cord.

3. An electrical cord comprising a conductor having a covering ofbraided strand material in which one side of the covering has apredetermined degree of interbraiding of the strands, the portions alongthe neutral bending axis of the cord having a lesser degree ofinterbraiding of the strands, and the side opposite the first mentionedside having the least degree of interbraiding of the strands.

'coil having the covering strands interbraided to a predetermineddegree, the inner portion or the convolutions of the coil having thecovering strands interbraided to a lesser degree, and means tending toretain the cord in helical form.

6. A retractile cord comprising 'a helically coiled conductor having acovering of braided F strands, the outer portion of a convolution hav-'ing the covering strands braided progressively one strand over onestrand and under the next while the inner portion of a convolution hasthe covering'strands braided progressively one strand over two strandsand under the next two.

7. An electrical cord comprising a helically coiled conductor having acovering of braided strands, the outer portion of a convolution of thecovering being interbraided progressively one strand over one strand andunder the next, and the inner portion of a convolution having thecovering strands interbraided to a lesser degree.

8. An electrical cord comprising a helically coiled conductor having acovering of braided strands, the outer portion of a convolution of thecovering being interbraided progressively one strand over two strandsand under the next two, and. the inner portion of a convolution havingthe covering strands interbraided to a lesser degree.

WILLIAM T. BARRANS. PAUL 2M. COLE. BYRON P. GERARD.

